Copper-nickel alloys of high-yield strength

ABSTRACT

Corrosion-resistant, cast (and wrought) copper-nickel alloys containing special amounts of nickel, chromium and silicon are characterized by high-yield strengths-e.g., from about 40,000 and upwards of 50,000 p.s.i. This compares with substantially less than 40,000 p.s.i. for conventional copper-nickel alloys in commercial use. Heat treatment not required to develop strength; thus, associated problems are obviated.

United States Patent Badia et al.

[151 3,635,702 [4 1 Jan. 18, 1972 COPPER-NICKEL ALLOYS OF HIGH- YIELD STRENGTH Frank A. Badia, Ringwood, N.J.; Frank J. .Ansuini, Suffern, NY.

Inventors:

Assignee:

New York, N.Y.

July 1, 1968 Filed:

Appl. No.:

US. Cl ..75/159, 29/199, 75/154, 75/157, 75/l57.5, 148/325 Field ofSearch ..75/153, 159, 154, I57, 160, 75/161, 162, 164, 157.5; 148/32, 32.5; 29/199 References Cited UNITED STATES PATENTS 11/1947 Smith ..75/159 12/1956 Pease.... ....75/l59 6/1959 Woolard... ....75/l59 11/1962 Shepherd ..75/159 The International Nickel Company, Inc.,

3,253,911 5/1966 Cairns ..75/159 FOREIGN PATENTS OR APPLICATIONS 338,676 11/1930 Great Britain ..75/159 61,686 9/1948 Netherlands ..75/159 OTHER PUBLICATIONS Transactions of ASM, Vol. 60, 1967, pages 395- 401, 403, 407-408 Trans. of AIME, Inst. of Metals Div., Vol. 175, Feb. 1948 pages 283- 295 Primary ExaminerCharles N. Lovell Attorney-Maurice L. Pinel [57] ABSTRACT 15 Claims, 2 Drawing Figures PATENIED 1m 8 W2 m H 0 0 o m 1 6 mm w 5 1 0w L ma H m m m m w w m w m 55906;- MCKEL lllllllllllllllllllllllllllllllllllllll 5 IO Z5 zqooo PEIPcE/vr Morel T vMW/HIN A m #4 a K MM m V1 B COPPER-NICKEL ALLOYS F HIGH-YIELD STRENGTH Cast copper-nickel alloys by virtue of their excellent resistance to the corrosive effects of salt water, good weldability, adequate ductility, etc., have found extensive application in marine environments for a most considerable number of years. Propellers, impellers, housings, flanges, elbows, tees, etc., are illustrative of such cast articles, articles which find constant use. Commonly termed cupronickels," these alloys have served well but labor under the drawback of affording but limited yield strengths, about l5,000-l8,000 p.s.i. being typical. There is one cast alloy of higher yield strength, about 30,000 p.s.i., but it is of the heat treatable type and suffers from other drawbacks, e.g., it is section size sensitive. Thus, under operating conditions which by necessity demand higher strength materials, currently available cast copper-nickel alloys are, of course, unsuitable. Accordingly, the present invention is addressed primarily to the specific objective of boosting this strength plateau to as high as 50,000 p.s.i., but doing so while maintaining an acceptable level of other desirable properties for which the conventional cast cupronickels are noted.

Incident to the subject development, one of the approaches initially pursued was the recent technological advance brought about in respect of the wrought" copper-nickel alloys of the 70/30 type as described in an article authored by F. A. Badia, G. N. Kirby and S. R. Mihalisin, Transactions of the ASM, Vol. 60, pp. 395408 (1967). Incorporation of chromiurn in amounts from about 2.4 to 3.8 percent was found upon simple air cooling to result in a most substantial yield strength increase in respect of the standard wrought alloys-from a chromium-free level of about 18,000 p.s.i. to over 40,000 p.s.i. for alloys at the lower end of the chromium range and to over 50,000 p.s.i. for alloys of higher chromium. Yield strength aside, this prior development offered other significant commercial advantages. For example, age hardening (as theretofore elsewhere proposed) was not required. And, elimination of heat treatment is particularly beneficial in respect of welded structures for reasons too well documented to dwell upon herein. But it should be at least pointed out that to heat treat substantial size castings is impossible at times and usually difficult at best. Thus, problemsattendant such heat treatments were avoided-the alloys being-so to speak-selfdispositive.

It soon became apparent, however, that what seemed to be the answer for the "wrought" alloys was not the panacea for the cast versions. Cast copper-nickel alloys containing, say, 3 percent chromium, were objectionable for various reasons, including the fact that they were characterized by poor fluidity and microporosity. Too, though not all applications require cast alloys which are weldable, at the 3 percent chromium level weld cracking was experienced virtually every time. And at lower percentages of chromium, weld cracking too often occurred to remove the serious concern and uncertainty as to whether a given cast alloy would be weld-safe.

In any event, it has now been discovered that cast coppernickel alloys of exceptionally high yield strength can be obtained provided the alloys are of special composition, particularly with regard to chromium and silicon, and also nickel, as detailed herein. These alloys are devoid of detrimental second phases and microporosity, exhibit good fluidity, afford satisfactory ductility and toughness, do not require hardening heat treatments and if a proper amount of zirconium is present, are readily weldable. Moreover, the high level of yield strength, 40,000 p.s.i. and above, consistently obtains throughout a relatively wide range of cast section sizes, e.g., one-half to 2 inches in thickness. Thus, alloy strength is insensitive to section size, an excellent attribute of any cast alloy. In addition, it is particularly noteworthy that as an attendant feature of the overall invention and as a direct consequence of the research conducted in respect of the cast alloys, a new group of high strength wrought" cupronickels also evolved as will be described herein.

It is an object of the present invention to provide high strength, cast copper-nickel alloys.

The invention also contemplates providing corrosion-resistant, weldable, copper-nickel alloys in both the cast and wrought forms possessing yield strengths in excess of about 40,000 and as high as 50,000 p.s.i. or more, the alloys also being characterized by satisfactory ductility, toughness, etc.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawing in which:

FIGS. l and 2 depict curves illustrating the effect of nickel content on yield strength and tensile elongation of cast and wrought copper-nickel-chromium-silicon alloys, respectively.

Generally speaking and in accordance herewith, the present invention contemplates high strength copper-nickel alloys containing (in percent by weight) about 9 percent or 10 to 38 percent nickel, with the proviso that the nickel content is (a) at least 20 percent, and most advantageously at least 28 percent, for east alloys, but (b) does not exceed 30 percent, and

, most beneficially is not in excess of 27 percent, for alloys in wrought form, about 1 to 2.1 percent chromium, about 0.2 to 0.6 percent silicon, up to 0.8 percent zirconium, up to 3 percent manganese, up to 0.5 percent titanium, and the balance essentially copper. In applications requiring cast alloys to be welded, the alloys should contain about 0.05 percent zirconium or more. In addition, up to 5 percent cobalt, up to l percent columbium, up to 0.5 percent aluminum, up to 2 percent tin and up to 2 percent zinc can be present. Small amounts of carbon can be tolerated. However, constituents such as bismuth, lead, selenium, tellurium, sulfur, nitrogen, hydrogen, etc., should be maintained at low levels consistent with good processing practice. Too, the use of calcium for deoxidation purposes is not recommended since it tends to detract from ductility and impact resistance, and has brought about heat affected zone (HAZ) cracking upon welding.

The respective roles of chromium and silicon apparently involve an interplay therebetween, a coaction or cooperative effect which is thought to produce a synergistic result. By way of background in understanding this aspect, the authors of the ASM article mentioned herein established that copper-nickel alloys (l/l6-inch sheet) of the 70/30 type and which contained but 1.2 percent chromium exhibited a low yield strength of 29,400 p.s.i. upon air cooling. It was not until an amount of chromium above about 2.5 percent was used that a yield strength on the order of 50,000 p.s.i. was achieved. To be sure, alloys subjected to a vermiculite cool offered higher strength at corresponding chromium levels but, as will be appreciated by those skilled in the art, such cooling methods are highly undesirable and, in a commercial sense, quite impractical.

In the same treatise the authors further reflect that attempts were made to use supplemental elements in an endeavor to attain still higher strengths. Silicon was one of such auxiliary constituents but it was not found to impart any appreciable benefit, a point since confirmed as will be shown by data herein.

In accordance with the present invention, however, a contra effect is seemingly involved. With substantially lower chromium contents and provided silicon is present in an amount of at least 0.2 to 0.6 percent, high yield strengths are readily achieved. In this connection, when chromium is at the lower end of its range, say from 1 to 1.25 percent, a minimum silicon content of at least 0.35 percent is most advantageous in reaching the highest yield strength. Conversely, when the silicon content is from about 0.2 percent to about 0.35 or 0.4 percent, the minimum chromium content should be about 1.4 percent. For cast alloys, chromium levels: above about 1.7 percent do not offer any appreciable benefit in strength, a range of l or 1.2 to 1.7 percent being highly satisfactory for both cast and wrought alloys. While in some instances the silicon content may be as high as 0.7 percent, it is deemed beneficial that the silicon content not exceed 0.6 percent to thereby minimize the possibility of weldability difiiiculties.

The amount of nickel present must be controlled depending upon whether a cast or wrought alloy is desired. The nickel content should not be less than 20 percent for cast alloys; otherwise, unacceptably low yield strengths can result. It is considerably significant that the nickel content be at least 28 percent for castings since it has been determined that in cast was used. On ladling, the alloys tend to form a relatively heavy skin. To offset this, the use of a baffled ladle (teapot) is recommended since it simulates bottom pouring and minimizes interference from this surface skin.

alloys nickel imparts its maximum strengthening effect over a 5 Testing consisted of a determination of tensile properties, range of about 28 to 35 percent. Moreover, within this latter p icate 2 2411811 iameter n ile bars being used. The nickel range the allows are more ductile, notwithstanding they compositions, yield and tensile Strengths and il l ng concurrently exhibit greater strength. This is in contrast to lion are given in table mill!ded in table I are o g ys usual metallurgical behavior in which increases in strength are E and G taken from the ASM Transactions article Y attained at the expense of ductility. The effect of nickel in 7, 3 and referred to above -l Alloys ldemlfied y respect of cast alloys as to strength and ductility is graphically merals are within the scope of the cast alloys of the invention depicted by the curves in FIG. 1. These curves are based on a whereas those Preceded y 31cm" are TABLE 1 Percent P.s.i. El Ni Cr Si Mn Fe Zr Cu Y.s. U.I.S. percent 30. 6 0. 1 0. 03 0. 3 0. 48, 200 44 31. 1 0. 1 0. 34 0. 5 0. 50, 300 47 31.3 0. 1 i 0.34 0.15 0. 5 50,400 30 2s. 5 3.15 0.15 0. 66 0. 7 89. 900 26 30. 3 3. 55 0. 34 0. 70 0. 9 02, 900 25 30. 4 3. 25 0.48 0. 7 0. 78, 900 21 31. 8 1. 0.07 0. 5 0. 5 (i9, 300 35 14. s 1. 37 0. 45 (0. 4) (0. 7 10 50, 000 13 21.4 1.65 0.04 0.41 0. 7 .A. .000 20 30. 7 1. 0. 0. 5 0. .A. 70, 000 27 30. 1 1. 55 0. 52 0. 7 0. .A. 83,700 27 31. 5 1. 95 0. 44 0. 7 0. .A. 77. 600 25 30. 0 2. 00 0. 51 0. 8 0. .A. 79, 100 24 21. 7 1. 47 0. 0. 42 0. 69 11 67,800 14 25. 7 1. 0. 45 (0. 4) (0. 7) 10 71, 500 13 35. 0 1. 50 0.47 (0. 4) (0. 7) .10 81,600 20 41. 6 1. 50 0. 50 0. 42 0. 69 11 75,000 20 No'rEs.-N.A.=None added. Balance=Balance of composition essentially in parentheses=NominaL copper and impurities. Figs.

group of alloys in which the constituents, apart from nickel, 35 In respect of the data in table I, alloy A is representative of a were maintained over the following narrow ranges of composition: 1.37 to 1.6 percent chromium, 0.35 to 0.6 percent silicon, 0.4 to 0.54 percent manganese, to 0.69 to 0.9 percent (nominal) iron, balance copper and impurities.

The role of nickel in the wrought alloys is in marked contrast with its function in the cast versions. As is illustrated in FIG. 2, nickel confers its strongest influence with respect to strength over the rangeof about 18 percent or 19 to 27 percent. As can be seen from the curves, a loss of strength is experienced with nickel contents above about 27 percent in the wrought alloys. This nickel role not only differs from its mode of behavior in the cast alloys but is also quite different from that role portrayed in the high-chromium alloys discussed in the ASM article referred to above herein. In the case of these latter alloys, :1 minimum nickel content of 28 or 30 percent was much preferred for best overall properties, including strength. That this is not the case with the subject alloys is clear from FIG. 2, which also indicates that ductility does not diminish as the strength is increased by higher nickel levels. As with the cast compositions, ductility also increases. The curves in FIG. 2 are based on alloys containing, in addition to the varied nickel content, 1.37 to 1.5 percent chromium, 0.45 to 0.5 percent silicon, 0.4 to 0.42 percent manganese, about 0.7 percent iron, with the remainder being copper and impurities.

For the purpose of giving those skilled in the art a better appreciation of the invention, the following illustrative data are given.

Using a high-frequency induction furnace and magnesia crucible, a series of cast copper-nickel alloys were prepared in which electrolytic copper, electrolytic nickel, electrolytic iron and remelt stock were used as a basic charge. Upon forming a melt, 0.05 percent silicon was introduced as a preliminary deoxidation step and to minimize subsequent loss of more reactive metals. At a temperature of about 2,S00 F. manganesetelectrolytic or ferroalloy), chromium (vacuum grade or as n Ni-SO percent Cr master alloy) and silicon were added. Upon reaching a temperature of about 2.550 F. a final dcoxidant, usually 0.05 percent titanium. was plunged into the bath and thcreaftcr the melts were poured into a ladle and then into dry sand molds. A single keel block pattern 6%" 10") conventional cast cupronickel alloy, the yield strength thereof being at a low 14,500 p.s.i. Increasing the silicon content to an amount within the invention, to wit, 0.34 percent, (alloys B and C) did not impart any appreciable strengthening effect to conventional alloy A. This is consistent with prior are findings, although it is to be understood that such findings also reflect that considerably higher silicon contents do confer high strength in cast cupronickels (T. E. Kihlgren, Trans. Amer. Foundrymens Assn., Vol. XLV, pp. 225-260, 1937). For example, yield strengths of 50,000 p.s.i. have been reached in respect of standard alloys but with silicon levels of about 0.75 percent or more, silicon percentages at which welding difficulties tend to ensue.

Alloys D and E (alloys taken from the ASM treatise) reflect that in wrought high-chromium cupronickels (3-5.5 percent chromium) increasing the silicon content from 0.15 percent (alloy D) to 0.34 percent (alloy E) did not result in any significant increase in yield strength. Using alloys D and E as a basis of general comparison, cast alloy F of high chromium content also shows this same type of behavior. Alloy H is indicative of the fact that raising the chromium level to 1.2 percent in wrought low-silicon alloys leaves much to be desired by way of strength. With respect to alloys H and J, the former illustrates that for cast alloys nickel contents on the order of about 14.8 percent fail to afford a minimum yield strength of 40,000 p.s.i., irrespective of the fact that both the chromium and silicon levels are otherwise well within the subject invention. Alloy .1 demonstrates that though the percentages of nickel and chromium be within the scope of the invention low yield strengths still obtain in the presence of silicon contents appreciablybelow about 0.2 percent.

With regard as to what might be expected concerning consistency of strength over a fairly wide range of section size, in table II shown below there are data given for alloys both outside the invention (alloys M, N and O) and alloy 8, an alloy higher ductility would be required up to 27 percent or 28 percent nickel can be used while still retaining a very high strength plateau. It should be pointed out that whereas alloy H represents a composition outside the present invention for within the invention. These data show that alloys meeting the cast alloys it is nonetheless within the wrought alloy composicompositional requirements of the invention are relatively intions contemplated. The converse is true with respect to allo sensitive to section size as opposed to the considerable vari- 7 for, as can be seen, the strength level has dropped below the ance experienced with those alloys the chemistry of which de- 40,000 ,i, ini m, Thi do ntrend ontinue at hi he parts from the invention as in the case of alloys M and N (low percentages f i k l as evident fro ll K and FIG 2 SiliCOn) and alloy 0 Chromium) The data are based p n While, as indicated before herein, there are numerous appli- 55-inch and z-iheh'thiek Wedges apprexlmately 7 lhehes cations in which cupronickel castings are not welded, there lehgth- Machined tensile Speelmehs were ehtamed from the are nonetheless substantial areas of utility in which weldability middle of each least Plate e P p of p Apart becomes of paramount significance. In accordance herewith, from the chemistry g1veh table "1 alloy 8 Contained provided the cast alloys contain zirconium in an amount of p e zh'eohlum and each of the alloys eohtamed about 0.05 Percent or higher, satisfactory weldability charactltamum m an mount p to about n r" ethsfwlse the teristics follow. This is illustrated by the following examples balance of the compositions was copper plus impurities. and data TABLE 11 Percent P.s 1

Cast Section, El. Alloy Ni Cr Si Fe Mn inches Y.S. U.T S percent y 32, 700 64, 800 27 M a4. 4 1. 65 0. 04 0. 70 0.40 g f 1, 5 N 20.5 1. 70 0. 04 0. 74 0. 42 98 7, 0 7, 9 s 20. 0 1. 55 0. 27 0. 70 0. 51 5 23 g 2 1 0 -6 0 30.6 0.80 0. 31 0.63 o.1 5 43,700 72' 700 25 With regard to wrought alloys contemplated herein, a series E E b 28 7 of specimens was prepared in the manner described in coneopper'hlekel eastlng n ining a out percent nection with the alloys in table I. Thereafter, the cast ingots 3 5 hlekeh Pefeeht ehromluhh Percent e' 9- P were soaked at a temperature of about l,900 F. for 1 hour, eehl manganese, (L60 Pereehtlroh, P h i and hot-rolled down to a fil-inch thickness, air-cooled, cold-rolled the balance eesehtlally pp I10 llfeohlum g been to one-eighth inch thick, annealed for 1 hour at l,700 F aire fi was subleeted m autegeheus TIG e Weldlhg e cooled, cold-rolled to 1/16-inch strip, and finally annealed at a This 15 p y more as a Screening e and "W rulmmg temperature of approximately l,700 F. for 1 hour followed 40 a head on the surfaeeef a Plate specimen a tungsten once again by air cooling. To simulate the cooling rate to be men electrode. In the instant case, a travel speed of about 16 expected in respect of l-inch plate, a second group of inches per minute was used,the shleldmg gas being argon supspecimens involved inserting a l/ l 6-inch piece of stri plied at a volume of 25 cubic feet per hour. A lla-lnch tungsten between two A'll'lCh pieces which were then bolted together. electrode was employed, the arc length being about 0.05 lnch. This sandwich structure was then annealed at 1,700 F. for l 45 The bead surface was ground, etched, and then examined at a hour and air cooled to room temperature. The l/ 16-inch strip magnification of about 10 to 30. A crack was found in the was removed and tensile tested, the results being reported weld joint with several cracks being found in the heat affected under the caption-4%" Air Cool-in table III together with zone (HAZ). This evidence reflected that the weldability the results of the first series (one-sixteenth inch) of specimens. characteristics of the alloy would not be satisfactory for appli- (Alloys 9 and 10 contained 0.1 percent and 0.02 percent zir- 50 cations requiring weldable castings, (particularly since the conium, respectively, the other alloys containing zirconium in conditions of the TlG bead procedure are not at all severe) amounts given in table 1. Each of the alloys contained up to although the alloy would be suitable for cast articles which 0.1 percent titanium). were notto be welded,

TABLE III Percent An air c001 P air cool Si Fe Mn Y.S., U.T.S., EL, Y.S., U.T.S., EL, K s.i. K s.i. percent K s.i. K s.i. percent 0. 60 (0.7) (0. 4) 41. 9 64.1 17 50.1 70 16 0.45 (0.7) (0.4) 45.6 68.8 24 49. 5 70. 6 21 46. 5 68. 5 23 50. 1 69. 6 0. 45 0. 69 0.42 52.3 78.4 24 67.2 80.1 22 52. 7 79. 1 25 57. 2 79. 4 23 h 25.7 1. 50 0. 45 (0. 7) (0.4) 51. 8 83.3 26 58. 7 88. 7 24 51. 7 83.1 28 58. 2 88.6 24 10 30.3 1.63 0.30 0.89 0.41 41.5 77.2 33 40. s 76. 3 33 1. 7 35. 0 1. 50 0.47 (0. 7) (0.4) 37. 7 74, .J 35 47. ii 83. 6 30 37. 4 74. 6 33 46. 6 82. 4 35 K 41.0 1. 0. 0.150 0.44 34.0 73.0 86 39,1 77,0 36 34. 7 73. 2 30 38. 6 75. (i 35 The data given in table Ill considered together with the EXAMPLE ll curves in FIG. 2 reflect that excellent strength and combinations of strength and ductility are readily obtainable. Where strength is of paramount consideration a nickel range of from 17 to 23 percent is extremely satisfactory. Where a somewhat A cast plate of composition similar to that used in example I but to which zirconium was added was also subjected to the T16 bead test. The plate specimen contained about 29.0 percent nickel, 1.30 percent chromium, 0.37 percent silicon, 0.35

percent manganese, 0.06 percent iron, 0.03 percent titanium, Although the present invention has been described in conand 0.03 percent zirconium, the balance being essentially junction with preferred embodiments, it is to be understood copper. Again, a crack was found in the weld although no that modifications and variations may be resorted to without crack was found in the heat affected zone. Cast plates fivedeparting from the spirit and scope of the invention, as those eighths inch in thickness by 2% inches in width and about 4 5 skilled in the art will readily understand. Such modifications inches long of the same alloy composition were butt welded. and variations are considered to be within the purview and The plates were beveled along the 4 inches edge at an angle of scope of the invention and appended claims. about 30 and were placed upon a copper-faced steel platen, We claim: the distance therebetween being maintained at about one-sixl. A copper-nickel base alloy characterized in having a yield teenth inch. The plates were restrained by clamping to the strength of at least about 40,000 p.s.i. in both the cast and platen. A flux-covered electrode successfully employed in wrought conditions, the yield strength obtaining throughout welding the previously developed high-chromium (2.4-3.8 the section sizes of from at least one-half inch to 2 inches in percent) wrought cupronickels was used, th composition f thickness, said alloy consisting essentially of from about 9 to the flux being as follows: 20 percent calcium carbonat 20 38 percent nickel, the nickel content being at least 20 percent percent cryolite, 19 percent manganese carbonate, 10 pep in cast alloys but not in excess of 30 percent for alloys in the cent chromium, 19 percent titania 4 percent of a master wrought condltloni PP 1 to Percem Q -"l i about nickel-silicon (28 percent silicon) alloy, 5 percent of a master P i P to p f llmomumi the nickel-titanium alloy (26 percent titanium) and 3 percent zu'comum not exceedmg about Percent 62.15! y i "P bentonite, with 15 percent sodium silicate solution having to 3 P manganese P to P F mamum' "P to 5 been added as a binder. The flux was baked on a core wire P e Cobalt. p w 1 P n columblum. p to Percent containing 31.8 percent nickel, 0.69 percent manganese, 0,60 aluminum P F 2 P i to 2 Plament and the percent iron, 0.10 percent silicon, 0.26 percent titanium, the balance essemlany copper f l andchl'omlum are balance being essentially copper. related such that when the slllcon content is from 0.2 percent Neither a preheat not a post Weld heat treatment was to about 0.35 percent the chrornlum content is at least 1.4 perployed and the temperature between passes was below 00 F cent and when the chromium ls from 1 to l.25percent the SH- Upon examination, no cracks were found in the weld or heat 15 at least Pbout p f I affected zone. This together with the T16 bead test indicated An alloy accordance with claim 1 m which the silicon that a slightly higher zirconium content should be used, if the come!" does 9 exceed about 9- P r alloy were to be used in environments necessitating highly alloy accordance Wlth clam 2 m whlch f nickel satisfactory weldable cast alloys. 30 content is at least 28 percent for cast alloys and not in excess of 27 percent for alloys in the wrought condition.

EXAMPLE 4. A cast alloy in accordance with claim 2 in which the Both TIG bead and butt welding tests were conducted as in nickel content is from 28 to percent. example II in respect of a cast plate(s) containing 0.06 percent 5. A cast alloy in accordance with claim 2 in which zirconizirconium, the balance of the composition consisting of about 35 um is present in an amount of at least about 0.05 percent, 29 percent nickel, 1.37 percent chromium, 0.39 percent silwhereby weldability is enhanced. icon, 0.35 percent manganese, 0.60 percent iron, 0.03 percent 6. A cast alloy in accordance with claim 5 having high retitanium and with the remainder being essentially copper. No sistance to impact by virtue of the fact that the zirconium conevidence of cracking was found in the weld joint or in the heat te t, if n does not exceed 0.15 ercent. affected zone in either test. 7. A cast alloy in accordance with claim 3 in which the While the foregoing demonstrates the value of zirconium as chromium content does not exceed about 1.7 percent. to weldability, the amount thereof should be controlled in cast 8 A t all in rd n with claim 7 in which the alloys so as not to exceed, say, about 0.28 percent, since it haschromium is at least 1.2 percent. been determined that at least in cast alloys it detracts from 9. A wrought alloy in accordance with claim 2 in which the toughness. This is illustrated by the data given in table IV. i k l nt nt i fr m 19 to 27 er ent.

TABLE IV Percent C.V.N. Si Mn Fe Ti Zr Cu (ft.-lbs.)

0.39 0. 36 0. 0. 02 N.A. Balance-.. 00, 58, 57 0.37 0. 35 0.60 0. 03 0. 03 d0 61, 57, 52 0. 39 0. 35 0.50 0. 03 0. 06 ..do 7, 54, 46 0.36 0. 35 0.61 0.04 0. 06 -do 50, 0, 43 0.55 0.40 0. 80 0. 06 do 33, 6, 41 0.52 0.45 0. 82 0.04 0.20 .do 15.5, 16, 18 0.48 0. 40 0.80 0.04 0.27 .do 15, 15, 16. 5

N OTE.ThG compositions for Alloys 11, 12 and 13 are those given in Examples I, II and III, respectively. N.A.=Not added.

It is clear from the above data that relatively high zirconium 60 10. A wrought alloy in accordance with claim 2 in which the levels impair the ability of the alloys to absorb impact energy. nickel content is from 17 to 23 percent. Accordingly, it is considerably advantageous to maintain the 1 l. A wrought alloy in accordance with claim 3 in which the zirconium content such that it does not exceed 0.10 percent or chromium content does not exceed about 1.7 percent.

0.15 percent in cast alloys. For good workability and other 12. A wrought alloy in accordance with claim 11 in which benefits, zirconium should also be used in the wrought alloys the chromium is at least 1.2 percent.

in an amount of at least 0.01 percent or 0.02 percent. 13. A wrought alloy in accordance with claim 12 in which 1 As previously indicated herein the cast alloys can be used in the nickel content is from 19 to 27 percent.

such applications as propellers, impellers, housings, etc. With 14. A wrought alloy in accordance with claim 13 containing regard to the wrought alloys, salt water piping, heat exchanat least 0.01 percent zirconium.

gers, tube sh ts, condensers, etc, are illustrative of various 15. As a new article of manufacture, a welded structure in uses to which these alloys can be put. Of course, the wrought which at least one welded component is formed from an alloy alloys can be produced in various mill forms, including strip, in accordance with laim 5,

sheet, plate, bar, rod tubing, wire, extruded shapes, etc. 

2. An alloy in accordance with claim 1 in which the silicon content does not exceed about 0.6 percent.
 3. An alloy in accordance with claim 2 in which the nickel content is at least 28 percent for cast alloys and not in excess of 27 percent for alloys in the wrought condition.
 4. A cast alloy in accordance with claim 2 in which the nickel content is from 28 to 35 percent.
 5. A cast alloy in accordance with claim 2 in which zirconium is present in an amount of at least about 0.05 percent, whereby weldability is enhanced.
 6. A cast alloy in accordance with claim 5 having high resistance to impact by virtue of the fact that the zirconium content, if any, does not exceed 0.15 percent.
 7. A cast alloy in accordance with claim 3 in which the chromium content does not exceed about 1.7 percent.
 8. A cast alloy in accordance with claim 7 in which the chromium is at least 1.2 percent.
 9. A wrought alloy in accordance with claim 2 in which the nickel content is from 19 to 27 percent.
 10. A wrought alloy in accordance with claim 2 in which the nickel content is from 17 to 23 percent.
 11. A wrought alloy in accordance with claim 3 in which the chromium content does not exceed about 1.7 percent.
 12. A wrought alloy in accordance with claim 11 in which the chromium is at least 1.2 percent.
 13. A wrought alloy in accordance with claim 12 in which the nickel content is from 19 to 27 percent.
 14. A wrought alloy in accordance with claim 13 containing at least 0.01 percent zirconium.
 15. As a new article of manufacture, a welded structure in which at least one welded component is formed from an alloy in accordance with claim
 5. 